The Aichi D3A (Allied code name "Val") was a World War II dive bomber produced by the Aichi company in Japan. It was the primary carrier-borne dive bomber in the Imperial Japanese Navy in the early stages of the war, and participated in almost all actions, including Pearl Harbor.

In mid-1936, the Japanese Navy issued the 11-Shi specification for a monoplane carrier-based dive bomber to replace the existing D1A biplanes currently in service. Aichi, Nakajima and Mitsubishi all submitted designs, and Aichi and Nakajima were both asked for two prototypes each.

The Aichi design started with low-mounted elliptical wings inspired by the Heinkel He 70 Blitz. The fuselage looked quite similar to the A6M Zero, although the entire plane was built stronger to withstand the rigors of dive bombing. It flew slowly enough that the drag from the landing gear was not a serious issue, so fixed gear were used for simplicity. The plane was to be powered by the 529 kW (710 hp) Nakajima Hikari 1 nine-cylinder radial engine.

The first prototype was completed in December 1937, and flight trials began a month later. Initial tests were disappointing. The aircraft was underpowered and suffered from directional instability in wide turns, and in tighter turns, it tended to snap roll. The dive brakes vibrated heavily when extended at their design speed of 370 km/h (200 kn), and the Navy was already asking for a faster diving speed of 240 kn (440 km/h).

The second aircraft was extensively modified prior to delivery to try to address the problems. Power was increased by replacing the Hikari with the 626 kW (840 hp) Mitsubishi Kinsei 3 in a redesigned cowling, and the vertical tail was enlarged to help with the directional instability. The wings were slightly larger in span and the outer sections of the leading edges had wash-out to combat the snap rolls, and strengthened dive brakes were fitted. These changes cured all of the problems except the directional instability, and it was enough for the D3A1 to win over the Nakajima D3N1.

Pictured here is a 1:72 scale replica of an Imperial Japanese Navy Aichi D3A1 Val dive-bomber which was piloted by Lieutenant Commander Kakuichi Takahashi, who was embarked upon the aircraft carrier Shokaku, when it participated in the raid on Pearl Harbor in December 1941. Sold Out!

Historical Account: "The Slayer's Axe" - Shortly before 08:00 on the morning of December 7th, 1941, Japanese aircraft from six fleet carriers struck the Pacific Fleet as it lay in port at Pearl Harbor, and - in the ensuing two attack waves - wrought devastation on the Battle Line and on air and military facilities defending Pearl Harbor.

On board Arizona, the ship's air raid alarm went off about 07:55, and the ship went to general quarters soon thereafter. Shortly after 08:00, a bomb dropped by a high-altitude Kate bomber from the Japanese carrier Kaga hit the side of the #4 turret, glancing off and into the deck below starting a small fire which caused minimal damage.

At 08:06, a bomb from a Hiryu Kate hit between and to starboard of Turrets #1 & 2. The subsequent explosion, which destroyed the forward part of Arizona, was due to the detonation of the ammunition magazine, located in an armored section under the deck. Most experts seem to agree that the bomb could hardly have pierced the armor. Instead, it seems widely accepted that the black powder magazine (used for aircraft catapults) detonated first, igniting the smokeless powder magazine (used for the ship's main armament). A 1944 BUSHIP report suggests that a hatch leading to the black powder magazine was left open, with perhaps inflammable materials stocked nearby. A US Navy historical site history.navy.mil goes as far as to suggest that black powder might have been stockpiled outside of the armored magazine. However, it seems unlikely that a definitive answer to this question might be found. Credit for the hit was officially given to Japanese pilot Tadashi Kusumi. The cataclysmic explosion ripped through the forward part of the ship, touching off fierce fires that burned for two days. (courtesy: Wikipedia)